Multicontact connector having improved insert

ABSTRACT

MULTICONTACT ELECTRICAL CONNECTOR PART, WHICH IS ENGAGEABLE WITH A COMPLEMENTARY CONNECTOR PART, HAS A SHELL MEMBER AND AN INSERT IN THE SHELL. THE INSERT IS AXIALLY MOVABLE, TO A LIMITED EXTENT, IN THE SHELL AND IS RESILIENTLY BIASED IN THE DIRECTION OF THE MATING FACE OF THE INSERT. WHEN THE CONNECTOR PART IS MATED WITH THE COMPLIMENTARY PART, AND THE MATING FACE OF THE TWO CONNECTOR PARTS   ARE PRESSED AGAINST EACH OTHER, THE INSERT IS MOVED REARWARDLY WITH CONCOMITANT PARTIAL COMPRESSION OF THE SPRING SO THAT THE SPRING FUNCTIONS TO BIAS THE INSERT AGAINST THE INSERT OF THE MATING CONNECTOR PART.

Feb. 9., 1971 BARNHART ETAL 3,562,696

I MULTICONTACT CONNECTOR HAVING IMPROVED INSERT 5 Sheets-Sheet 1 FiledJan. 17, 1969 Feb. 9, 1971 I BARNHART ETAL 3,562,696

MULTICONTACT CONNECTOR HAVING IMPROVED INSERT 3 Sheets-Sheet 2 FiledJan. 17, 1969 MULTICONTACT CONNECTOR HAVING IMPROVED INSERT Filed Jan.17, 1969 9, 19.71 H. E. BARNHART ET 3 Sheets-Sheet 3 United StatesPatent 3,562,696 MULTICONTACT CONNECTOR HAVING IMPROVED INSERT HarryEdward Barnhart, Hummelstown, and Gilbert Douglas Ferdon, Harrisburg,Pa., assignors to AMP Incorporated, Harrisburg, Pa.

Filed Jan. 17, 1969, Ser. No. 791,977 Int. Cl. H011 13/52 U.S. Cl.339-60 1 Claim ABSTRACT OF THE DISCLOSURE .Multicontact electricalconnector part, which is engageable with a complimentary connector part,has a shell member and an insert in the shell. The insert is axiallymovable, to a limited extent, in the shell and is resiliently biased inthe direction of the mating face of the insert. When the connector partis mated with the complimentary part, and the mating face of the twoconnector parts are pressed against each other, the insert is movedrearwardly with concomitant partial compression of the spring so thatthe spring functions to bias the insert against the insert of the matingconnector part.

BACKGROUND OF THE INVENTION A conventional type of multicontactelectrical connector comprises a shell member, which is usually ofmetal, and an insert of an insulating material in the shell. Contactcavities extend through the insert from the rearward face thereof to themating face and electrical contact terminals are mounted in thecavities. When a connector part of this type is mated with acomplimentary connector part, the contact terminals in the two connectorparts are engaged with each other thereby to complete the circuits ofthe wires connected to the contact terminals.

High quality connectors of the type described above, particularly thoseintended for use in aircraft or under other critical circumstances, areusually of the sealed type in which the individual contact terminals inboth connector parts are sealed from the atmosphere. Such sealingrequires that sealing means of some sort be provided for each of thecontact cavities in the inserts at both ends of the cavity. The rearwardends of the cavities are often sealed by providing constrictions in thecavities which bear against the wires extending to the terminals mountedin the cavities and prevent the entrance of corrosive gages or the likeinto the cavities. The forward ends of the cavities, which open into themating faces of the inserts, are usually sealed by assuring that whenthe connector parts are mated, the two mating faces 'will be pressedfirmly against each other so that the resilient material, of which themating faces are formed, will be compressed to provide a sealsurrounding each of the cavities.

The present invention is directed to the achievement of an improvedsealed connector. It is an object of the invention to provide animproved multicontact electrical connector. A further object is toprovide a sealed electrical connector having means for maintaining theinterface seal of the connector not withstanding exposure to adverseenvironmental conditions. A still further object is to provide aconnector having means for offsetting the deleterious affects of agingof the insert. A still further object is to provide a connector havingmeans for compensating for the affect of compression set in the insertmaterial. A further object is to provide a connector having means formaintaining substantially complete mating of the contact terminals inthe connector parts when the parts are engaged with each other and formaintainice ing the parallelism of the contact terminals in theconnector parts.

These and other objects of the invention are achieved in a preferredembodiment thereof comprising a connector part having a metallic shellmember and an insulating insert in the shell. The mating face of theinsert is of a compressible material, such as a silicone rubber, so thatwhen the connector part is mated with a complimentary connector part,the mating faces of both parts will be compressed to provide sealingmeans in surrounding relationship to each of the contact terminals inthe connector parts. The insert is resiliently biased in the directionof its mating face by means of a spring interposed between a shoulder onthe insert and a shoulder on the shell. The strength of this spring issuch that when the part is engaged with a complimentary connector partthe mating face of the insert will be compressed and the insert willmove rearwardly in the shell against the biasing force of the spring.During use of the connector, if the insert material at the mating facethereof should change its physical properties, as a result of aging ortemperature cycling and thereby lose some of its ability to becompressed against the mating face of the complimentary connector part,the stored energy of the spring will continue to urge the mating faceagainst the mating face of the complimentary part thereby maintainingthe interfacial seal of the connector.

In the drawing:

FIG. 1 is a perspective view of a connector assembly in accordance withthe invention showing the two parts of the connector disengaged fromeach other and showing some of the parts exploded from the connectorshells to reveal their structural details.

FIG. 2 is a sectional side view of a connector assembly in accordancewith the invention showing the positions of the parts prior toengagement of the connector parts with each other.

FIG. 3, is a fragmentary view similar to FIG. 2, but on an enlargedscale, showing the parts engaged with each other.

Referring first to FIGS. 1 and 2 a connector assembly in accordance withthe invention comprises a plug part 2 and a receptacle part 4. The plugcomprises an upper shell section 6 and a lower shell section 8, theseshell sections being integral with each other by means of a web portion12 and an integral mounting flange 10. Shells of this type are usuallyof metal and may conveniently be manufactured by conventional diecasting techniques. A plurality of keys 14 are mounted in the webportion 12 of the plug 2 and are adapted to enter 'key receivingopenings 14 in the web portion 12 of the receptacle 4. These keys may beindividually oriented in any one of several possible orientations sothat the two parts of a connector assembly can be keyed to each other ina manner such as to prevent mismating of one connector plug with thereceptacle of a different connector assembly. The copending applicationof Harry 'E. Barnhart et al., Ser. No. 669,739, now U.S. Pat. 3,491,330discloses and claims a preferred method of mounting the keying means 14,14 in the web portions in the connector shells.

The upper shell section 6 is of generally polygonal cross-section andhas an opening extending therethrough from its rearward end 16 to itsforward end 18 for reception of the insert assembly 38 described below.As viewed in axial cross-section (FIGS. 2 and 3) this opening extendsinwardly with a uniform cross-Section 20 from the rearward end 16 of theshell and is constricted intermediate its ends by a shoulder 22.Adjoining the shoulder 22 is a relatively short section 24 of uniformcross-section, another rearwardly facing shoulder 26 at the end of theuniform cross-section portion 24, a further very short 3 reducedcross-section port 28, a diagonally extending shoulder 30, and a finalrelatively short portion of uniform cross-section 32. The forwardportion 34 of the opening has sidewalls which diverge slightly from thelongitudinal axis of the shell for draft purposes.

The insert assembly 38 comprises a forward portion 44 which is of aresilient rubber-like material, an intermediate section 46 which may beof a relatively firm plastic material, and a rearward or grommet portion48 which is again of a rubber-like material. Contact cavities extendthrough the insert from the rearward face 40 to the mating face 42thereof and electrical contact sockets 52 are mounted in these cavitiesin the plug portion of the connector assembly as shown. It will beunderstood that the principles of the invention can be employed if awide variety of shells and insert configurations, the disclosedconfigurations being of the type commonly used for connectors employedin critical air-craft installations.

The rearward section 48 of the insert assembly has a circumferentiallyextending collar 54 thereon which defines forwardly and rearwardlyfacing shoulders. When the insert is mounted in the upper shell portion6, and the plug 2 is not mated with the receptacle 4, the forwardlyfacing shoulder provided by this collar bears against the rearwardlyfacing shoulder 26 on the interior surface of the shell as shown in FIG.2. It will also be apparent from FIG. 2 that the intermediate section 46of the insert is contoured to provide surfaces which bear against theportions 28, 30 of the internal surface of the shell while the righthand portion of the forward section 44 is of reduced cross-section andprovides a rightwardly facing shoulder which is opposed to theleftwardly facing shoulder 37 on the internal surface of the shell.

A pair of springs 56 are mounted on the surface of the rearward insertsection 48 between the rightwardly facing shoulder of the collar 54 anda clamping plate 64 described below. Each of these springs comprises acontinuous formed section of beryllium copper strip or other suitablespring material, shaped to surround one-half of the insert section. Thesides 60 of the springs converge towards each other and are joined bysemicircular sections 58 on the upper and lower sides of the insertsections 48. Portions of the spring which bear against the oppositelydirected sides of the insert section are inwardly formed as shown insection 62 to provide bearing areas 63 which bear against the shoulderof the collar 54 and the internal surface of the clamping plate 64. Thisclamping plate is secured to the rearward end of the shell section 6 bymeans of suitable fasteners as shown and has a central opening of a sizesuch that the rearward end 48 of the insert assembly is permitted toproject therethrough.

The insert assembly and springs are assembled to the shell section 6 bymounting the springs on the rearward portion of the insert assembly andforcing the forward portion 44 of the insert assembly beyond theconstricted intermediate portion of the shell until the parts are in theposition of FIG. 2. The retaining plate 64 is then secured to therearward end of the shell section as shown.

The receptacle part 4 of the connector assembly is similar in manyrespects to the plug part and need not be described in complete detail.Accordingly, the structural features of the receptacle part 4 areidentified by the same reference numerals, differentiated by primemarks, as are used in the foregoing description of the plug part. Itwill be noted that in many instances, the structural parts of the plug 4are complimentary, rather than identical, to the corresponding parts ofthe receptacle; for example, the keying means in the receptacle partscomprises semicircular openings 14' adapted to receive the keys 14 andthat the portion 34 of the opening in the upper shell portion 6 isadapted to receive the projecting end of the upper shell portion 6 ofthe plug. The contact terminals in'the receptacle comprises contact pins52 which do not extend beyond the forward end of the connector part 4 sothat they are always surrounded and protected in accordance with commonpractice in the connector art.

In the disclosed embodiment, the receptacle connector part is notprovided with springs corresponding to the springs 56 of the plug partalthough the insert assembly in the receptacle part is structurallyidentical to the insert assembly 38 of the plug. Spacers 66 are,however, provided between the rearwardly facing shoulder defined by thecollar 54' of the receptacle insert and the forwardly facing surface ofthe clamping plate 64 of the receptacle. These spacers effectivelyprevent any axial movement of the insert assembly 38 in the receptaclewhile such axial movement is permitted in the plug.

As previously noted, the forward sections 44, 44, of the insertassemblies 38, 38' are of a suitable rubber-like material such as asilicone rubber. It will also be noted that the mating face 42 of theinsert assembly 38 of the plug projects slightly beyond the forward end18 of the plug 2 when the parts are disengaged while the mating face 42'of the insert assembly 38' projects slightly beyond the shoulder 36 ofthe receptacle. When the parts are completely mated, these mating facesare compressed to the extent necessary to provide a sealed interfacewhich moisture cannot readily penetrate and the possibility offlash-over between adjacent contact terminals will be minimized oreliminated. When the parts are mated as shown in FIGURE 3, thecompressive stresses generated at the interface cause the insertassembly 38 of the plug to be displaced rightwardly as viewed in FIG. 3,by a slight amount with accompanying compression of the springs 56. Byvirtue of the compression of these springs, the insert assembly 38 inthe plug is resiliently urged at all times toward insert assembly 38 inthe receptacle.

A particular advantage of the disclosed embodiment of the invention isthat the affects of Compression Set of the inserts at the mating face orinterface are nullified and the interfacial seal will not be lost ifsuch compression set takes place. Compression Set is generallyconsidered to be the loss of elasticity in a rubber-like material whichoccurs when the material is subjected to a continuous compressive loadand/ or to an elevated temperature. The degree of compression set in agiven material is commonly determined by providing a disc of materialoneinch in diameter and one-half inch thick, clamping this disc betweentwo parallel plates, moving the plates towards each other until they arespaced apart by a distance of three-eighths inches, heating the clampeddisc to a temperature of 257 F., and holding at that temperature for 24hours. The specimen is then unloaded, allowed to cool to roomtemperature, and its thickness is measured. For most rubber-likematerials, it will be found that the test specimen will not return toits original dimensions and will have a thickness somewhat less than theone-half-inch.

It will be apparent from the foregoing that if a connector dependsentirely upon compression of the interface material for the interfacialsealing, compression set in the insert material at the interface willreduce the effectiveness of the interfacial seal and possibly causefailure. In accordance with the instant invention however, the effectsof compression set in the inserts are counteracted by the compressedsprings 56 which partially return to their relaxed positions in theevent of compression set of the interface of the mated connector parts.It will be apparent that the hardness or resilience of the interfacematerial and the stiffness of the springs 56 must be judiciouslyselected to achieve both compression of the interface material andpartial loading of the springs 56 when the connector parts are matedwith each other. It has been found from experience that the forwardsection of the insert assembly can advantageously be made of a siliconerubber having a durometer hardness of about A50 to achieve interfacialsealing of the connector. The characteristics of the springs 56 shouldthen be selected to provide for retractile movement of the insertassembly 38 by an amount which is about twice the reduction in thelength of the insert when the parts are mated. In other 'words, if thehardness of the portion 4-4 of the insert is A50, the characteristics ofthe springs 56 should be such that when the parts are mated the entireinsert assembly will move rightwardly as viewed in FIGS. 2 and 3 againstthe biasing force of the springs by a distance which is twice thereduction in the length of the insert.

In the disclosed embodiment, the springs 56 are provided only in theplug portion of the connector assembly and are replaced by the spacer 66in the receptacle which effectively prevents any axial movement of theinserts in that member. If desired, springs can be provided in thereceptacle insert. It has been found, however, that springs need beprovided in only one part of the connector to maintain the interfacialseal under all ordinary conditions.

The insert mounted in the lower shell portion 8 in FIG. 1 differs fromthe insert 38 in the upper shell portion in that the lower insert isprovided with only two cavities 50a having coaxial contact terminals 52amounted therein. The rearward section 48a of this insert assembly alsomay be of metal rather than of insulating material since the outerconductors of a coaxial contact terminal are usually grounded to theshell member. The instant invention has an added advantage for coaxialconnectors in that the float or relative movement of the insert providedby the springs 56 function to maintain substantially complete engagementof the contact terminals of the plug with the terminals in thereceptacle and further to maintain parallelism of the terminals in theplug with those in the receptacle, In the case of coaxial contactterminals, such complete engagement of the terminals is particularlyimportant in order to maintain the electrical characteristics of theterminals when they are engaged with each other.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only.

We claim:

1. In an electrical connector assembly comprising a pair of matableconnector parts, each part comprising an insert and a shell insurrounding relationship to said insert, said insert having a pluralityof contact terminals therein and having a mating face and a rearwardface, said mating faces of said inserts being in abutting relationship,and the contact terminals being engaged, when said parts are mated, theimprovement to said connector assembly comprising:

a radially extending projection on said insert of one of said partsintermediate the ends thereof, said projection defining forwardly andrearwardly facing insert shoulder means.

forwardly and rearwardly facing shell shoulder means in said shell, saidforwardly facing shell shoulder means being proximate to the rearwardend of said shell and rearwardly facing shell shoulder means beingintermediate the ends of said shell, said projection being between saidshell shoulders, and

resilient means in surrounding relationship to said insert of said onepart and interposed between said forwardly facing shell shoulder meansand said rearwardly facing insert shoulder means and biasing saidforwardly facing insert shoulder means against said rearwardly facingshell shoulder means,

said mating face of said insert projecting beyond said leading end ofsaid shell when said forwardly facing insert shoulder means is againstsaid rearwardly facing shell shoulder means whereby upon mating saidparts, said insert means of both parts are moved against each other, andsaid insert means in said one part is moved relatively rearwardly in itsshell with concomitant compression of said spring whereby said springexerts a continuing force on said insert means in said one part urgingsaid insert means in said one part towards said insert means in saidother part.

References Cited UNITED STATES PATENTS 2,853,690 9/1958 Madison 339-453,404,365 10/1968 Obeissart 339- FOREIGN PATENTS 945,577 7/1956 Germany.5. 339-90 ERNEST R. PURSER, Primary Examiner J. H. MCGLYNN, AssistantExaminer

